1. Field of the Invention
The present invention relates to a method of constructing a sportssurface and the like having a compression strength, a bending strength, permeable to water, and showing no frost heaving.
2. Description of the Prior Art
A sportssurface in various kinds of sportsground, a sidewalk, a jogging course and the like have shown a problem in that their useable season and time are limited due to the weakening of a ground surface by rainwater.
In addition, recently, a lower layer road bed of a sportsground constructed with an artificial lawn or an artificial lawn filled with dried sands has been investigated.
So, the present inventor has tried to apply a soil-cement construction method to the above described sportssurface, lower layer road bed with an artificial lawn, sidewalk, jogging course and the like.
It has been, however, found that in the case where this soil-cement construction method is used for the formation of the above described sportssurface and the like, the following fatal disadvantages occur. That is to say, since soil-cement is naturally not permeable to water, a surface of a soil formed by said soil-cement construction method is remarkably wanting in water-permeability; the surface of the soil shows a frost heaving in an area where a temperature reaches below the freezing point; and the surface of the soil is broken due to coldness.
However, with regard to a relation between the water-permeability and the compression strength of soil cement, the compression strength is reduced with an increase of the water-permeability while the water-permeability is reduced with an increase of the compression strength; that is, an opposite relation exists between the water-permeability and the compression strength of soil-cement. Therefore, it is very difficult to solve the above described disadvantages.
In addition, since the water-permeability and the compression strength having a suitable bounding property and a cushiony property are required for a clay tennis-court, a sportssurface is most difficult to form.
The present inventor is a technician in the field of civil engineering and sports facilities and sufficiently knows that in order to use soil-cement in the formation of a sportssurface and the like, the above described disadvantages of soil-cement must be overcome.
However, the inexpensiveness of a soil constructed from soil-cement is incomparably attractive, so that the present inventor has ventured to challenge the above described difficulty and repeated the investigation for a long time. And, this time the present inventor obtained novel ideas through his investigation and experiments and achieved the present invention on the basis of the novel ideas.